Structure of electron-capture dissociation fragments from charge-tagged peptides probed by tunable infrared multiple photon dissociation.
In this study, we propose the first spectroscopic structural characterization of c-type ions produced by ECD of a peptide. The structure of c-type ions formed by electron capture dissociation and the overall mechanism leading to their formation are still a question of debate. Depending on the mechanism, c-type ions have been proposed to have either an enol-imine structure (-C(OH)NH) or an amide one (-C(O)-NH2). Since these ions are isomeric, mass spectrometry only cannot discriminate between them, but infrared spectroscopy can bring experimental evidence and help determine which scheme is operative. Using the coupling between a tunable free electron laser and a FT-ICR mass spectrometer, we show that c-type ions have an amide structure, characterized by an IR signature of the C=O stretch at 1731 cm(-1). This result is particularly interesting from the perspective of the elucidation of the ECD mechanism.
Frison
Gilles
G
Laboratoire des Mécanismes Réactionnels, Department of Chemistry, Ecole Polytechnique and CNRS, 91128 Palaiseau, France.
van der Rest
Guillaume
G
Turecek
Frantisek
F
Besson
Thierry
T
Lemaire
Joël
J
Maître
Philippe
P
Chamot-Rooke
Julia
J
D005583:Fourier Analysis; D013058:Mass Spectrometry / Q000379:methods; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D017785:Photons; D013055:Spectrophotometry, Infrared / Q000379:methods*
D010455:Peptides